Max load on a bearing for a machine skate?

[MrCrankyface]

I keep coming up to the fact that I want to know how much I can load a bearing.
In my current use case I want to make machine skates for moving machinery around, but I have no idea how much weight a bearing can take.
Let's say I make a regular square skate with 2 axles thus 4 bearings(one on each corner so to say).
How would I be able to calculate/know the load this theoretical skate could take?

For the example, let's say I've chosen to go with 6201-2z bearings.
I can see in SKF's spec sheet they should be able to statically take 3.1 kN and dynamically 7.28kN, but this tells me nothing as I don't know how to apply this unit.
I would very much appreciate if someone has some insight!

 

[JRaut]

1 kN (kilo-Newton) = 225 pounds

so: 3.1 kN (kilo-newton) = 697 pounds.

 

[MrCrankyface]

So in my example, a skate with 4 of these bearing should(in theory) be able to hold up almost 2800 pounds?
Quite impressive for such small bearings!

Any explanation on static versus dynamic?
I guess that static is just the bearing standing still and a constant weight applied on it but what would dynamic mean?

 

[JRaut]

Dynamic for bearings means short, temporary loads. SKF probably defines 'short' or 'temporary', but think impact.

Using them as machinery skates would be the static case.

 

[MrCrankyface]

Thanks! Much appreciated for the incredibly fast replies.

 

[DAT510]

Here's an explanation of Static and Dynamic Bearing Ratings.

Dynamic Load Capacity of Bearing

This article describes what is dynamic load capacity of a bearing, what is static load capacity of a bearing, bearing life, equivalent radial load on bearing. The dynamic load capacity of a bearing any bearing can be selected from the bearing catalogue where all details pertaining to the...

www.brighthubengineering.com

 

[pontiac428]

Run 8 bearings per skate and plan for all loads to be carried by 3 skates instead of 4, unless your floor is precision flat, one skate will wander off from the four like a lost sheep just traversing around. You can even use the bearings as wheels, right on the concrete. The simplest skate uses channel iron as the body, bearings as wheels, and bolts as axles.

 

[Ulma Doctor]

my monarch 10EE is setting on these right now as we speak...

Machine Skates, Light

I have a lathe to move soon and i wanted to make the move as easy as possible. i will have a forkilft on both the pick up and the shop ends to assist with the heavy lifting. sliding it into place will be a bit easier without the bulk of the forklift on the long side. the thought is to lower the...

www.hobby-machinist.com

 

[pontiac428]

These don't look very shiny anymore, but they got some big jobs done.

 

[nnam]

I went through a very similar problem not too long ago, trying to design my own heavy duty skate/dolly. It turns out that many heavy duty wheels don't use ball bearings or roller bearings at all. They use sleeve bearing, or sleeve cylinder rather.

Some cheap wheels use sleeve made of regular non-dom tube, so there is a weld line in there. It's crazy to think about it.

I imagine a bronze bearings or even copper tube would work very well

For your case of skates, where the diameter is very small and the ratio of bearing diameter to wheel diameter is high, sleeve bearings may not work very well.